1. Field of the Invention
The present invention generally relates to a planar motor device, a stage unit, an exposure apparatus and its making method, and a device and its manufacturing method. More particularly, the present invention relates to a planar motor device that has a mover and a stator and operates to drive the mover in a noncontacting manner in two-dimensional directions by electromagnetic force, a stage unit including a movable body to which the mover of the planar motor device is integrally attached, and an exposure apparatus incorporating the stage unit, and a method of making the exposure apparatus, and a device to be manufactured by using the exposure apparatus, and a device manufacturing method using the exposure apparatus.
2. Description of the Related Art
Conventionally, in a lithographic process for manufacturing semiconductor devices and liquid crystal display devices, an exposure apparatus that transfers a pattern formed on a mask or a reticle (hereunder generically referred to as a xe2x80x9creticlexe2x80x9d) through a projection optical system onto a substrate such as a wafer or a glass plate (hereunder generically referred to as a xe2x80x9csubstrate or waferxe2x80x9d), on which a resist is coated, has been used. This exposure apparatus is required to position the wafer at an exposure position with high precision. Thus, the wafer is held on a wafer holder by vacuum chucking, and the wafer holder is fixed onto a wafer table (that is, movable body) which structures a stage unit.
Recently, to position the wafer more quickly and with high precision without being affected by the mechanical accuracy of a guide surface, as well as to avoid mechanical friction and to prolong the life of the stage unit, a stage unit is being developed. This stage unit performs positional control of the wafer by supporting the movable body on which the wafer is placed above a supporting member by levitation and drives the movable body in a non-contacting manner. To accomplish such a stage unit, the key technology is the technique of levitating a mover above a stator of a planar motor device, and driving the mover in a predetermined direction (including a rotational direction) in an XY plane in order to move the mover. On driving such a planar motor device, a variable reluctance driving method and a Lorentz (electromagnetic) force method can be employed.
As a planar motor device used in the variable reluctance driving method, a motor as in a Sawyer motor, which has a structure of linear pulse motor s using the variable reluctance driving method respective to two axes being combined with each other, is the current mainstream. With the linear pulse motor using the variable reluctance driving method, it has a stator structured of; for instance, a plate-shaped magnetic substance having a gear tooth port ion (with an uneven shape) arranged along the longitudinal direction in equivalent intervals. It also has a mover that has a plurality of armature coils having an uneven portion different in phase with the gear tooth portion of the stator. The plurality of armature coils are arranged opposing the tooth portion of the stator, and are connected via a permanent magnet. And, the mover is driven by utilizing a force generated so as to minimize the magnetic reluctance between the stator and the mover at each point. That is, by adjusting and controlling the value and phase of pulse current supplied to each armature coil, the mover can be driven stepwise in a stepping operation.
Such a Sawyer type motor is configured of combining linear pulse motors that respectively correspond to 2 axes, on a moving plane. The driving portion which drive the mover movable in a plane in each axis direction, however, is separated from each other, thus making the mover heavy. To improve such inconvenience, an improved planar motor that can be moved on a plane by a single driving portion is being developed.
Also, with the planar motor device based on the Lorentz force method, the driving force is obtained by utilizing a Lorentz force F. This force is generated in the direction determined according to Fleming""s left hand law in the presence of an electric current I and a magnetic flux density B, which are perpendicular to each other, and expressed by the following equation:
F=Ixc3x97Bxc3x97Lxe2x80x83xe2x80x83(1)
In this equation, F designates a force generated on a current path; and L denotes the length of the current path. A conventionally proposed Lorentz force driving planar motor device is disclosed in, for example, the U.S. Pat. No. 5,196,745. With this planar motor device, magnets are respectively arranged so that the adjacent pairs of magnetic arrays alternately have the opposite polarity in the X-axis direction on a mover (or a stator). The magnets in the Y-axis direction are arranged in the Y-axis direction so that the adjacent pairs of magnetic arrays alternately have the opposite polarity, without the array intersecting that of the X-axis direction. Also, on a stator (or a mover), multi-phase coils for driving operations in the X-axis direction are arranged along the X-axis while multi-phase coils for the Y-axis direction are arranged along the Y-axis direction without the array intersecting with those of the X-axis direction. Thus, the thrust in the X-axis direction is generated by generating a Lorentz force, by sending an electric current to the multi-phase coil oppositely facing the magnets used for driving operations in the X-axis direction. And, the thrust in the Y-axis direction is also generated by generating a Lorentz force, by sending an electric current to the multi-phase coil oppositely facing the magnets used for driving operations in the Y-axis direction.
Among the conventional planar motor devices described above, the planar motor devices employing the variable reluctance method obtained high thrust between magnetic substances or between a magnetic substance and a permanent magnet by magnetic attraction or by repulsive force. It was, however, essentially difficult to reduce thrust variation, that is thrust cogging, when the current was not supplied to create a magnetized state. Furthermore, thrust generated by current excitation varies with the movable position. Therefore, to stabilize the thrust force that varies with the movable position, a higher level of a current pattern was required.
Also, the variable reluctance motor usually is configured of what is called an iron core coil, which is formed of winding an armature coil around a magnetic substance. Since it has a high armature coil inductance, the response time is slow; therefore a high voltage power supply is required to increase the response time, depriving the motor of its efficiency.
Furthermore, with the iron core coil, magnetic saturation of the iron core is caused due to the current flowing through it, so it is difficult to obtain the thrust linearity in a high current region making the design of the control system complex.
Meanwhile, with the conventional Lorentz force driving planar motor device, it excels in controllability, thrust linearity, and positioning ability. However, due to the limitation of the magnetic and coil array, the number of magnets and coils that are used for driving operations cannot be increased, therefore, it is difficult for this planar motor device to increase the thrust to be generated. Accordingly, it is difficult to move the mover, which carries an object of a certain weight such as a wafer holder or a substrate table, at a high speed.
Also, in order to use the planar motor device based on the variable reluctance driving method for precise positioning and to achieve high speed positioning, a large driving force is necessary. Naturally, a large current needs to be supplied to the armature coil. This, however, results in increasing the amount of heat generated in the armature coil. Such an increase in the amount of heat generated in the armature coil similarly occurs in the case of the planar motor device employing the Lorentz force method, in which the armature coil has to be supplied with a large current so as to obtain high thrust. Therefore, in consideration of the environment for a precise positioning system, it is essential for the planar motor to have a cooling system designed, and reduce thermal influence caused by the motor.
Furthermore, in the case of structuring a precise positioning stage with a planer motor device using a variable reluctance driving method, bearings, such as air bearings, to levitate the stage are essential. However, the planer motor device employing a variable reluctance driving method has a driving principle utilizing magnetic attraction as a driving force. The distance between the mover and the stator, therefore, is set at a very small value. The magnetic attraction force between the mover and stator serves as a reaction force against the stage levitation force by the air bearings. As a result, the amount of air supplied to levitate the stage and the power consumption of the air pump that supplies the air, are increased. In the case of using a planar motor device employing the Lorentz force driving method, when it is used for the driving source of the stage, it is desirable that the power consumption for levitating the stage is reduced.
The present invention has been made in view of the conditions above. Accordingly, a first object of the present invention is to provide a planar motor device that excels in controllability, thrust linearity, and positioning ability.
A second object of the present invention is to provide a stage that can perform and control high precision positioning of an object mounted on stage.
Also, a third object of the present invention is to provide an exposure apparatus that can perform high precision exposure by performing high precision positioning of a substrate and.
Finally, a fourth object of the present invention is to provide a device on which a fine pattern is formed with high accuracy.
To achieve the foregoing objects, according to a first aspect of the present invention, there is provided a first planar motor device comprising: an armature unit including a plurality of armature coils arranged in a matrix shape along a guide surface, which have a rectangular current path; and a magnetic pole unit arranged opposing the armature unit with respect to the guide surface, which has a plurality of thrust generating magnets having a rectangular magnetic pole surface with a side length longer than an arrangement period of the armature coil and is not equal to an integral multiple of the arrangement period, the plurality of thrust generating magnets arranged in a matrix shape in an arrangement period of an integral multiple of the arrangement period of the armature coils and having a different adjacent polarity of the magnetic pole surface in a row direction and a column direction, and the armature unit and the magnetic pole unit relatively move in a direction along the guide surface.
In the case of the first planar motor device of the present invention, to generate an efficient magnetic flux, that is to generate a magnetic circuit with a high magnetic density, a magnetic circuit which reluctance is low is structured. This is structured, by arranging the thrust generating magnets in a magnetic pole unit in the shape of a matrix, so that the polarities of adjacent magnet pole surfaces alternately differs from each other. And, in the armature coil unit, the armature coils are arranged in the shape of a matrix, and the amount and direction of the Lorentz force generated in the armature coils are changed by changing the amount and direction of the current being supplied to the armature coils. Accordingly, there are no exclusive driving direction of the respective thrust generating magnets arranged in the magnetic pole unit, and the respective armature coils arranged in the armature unit. Consequently, when the magnetic pole unit an d the armature unit relatively move in a desired direction, every thrust generating magnets and armature coils opposing these magnets can be used for moving them in the desired driving direction. This allows motor driving by a high thrust.
With the first planar motor device of the present invention, the matrix-shaped arrangement period of the thrust generating magnets of the magnetic pole unit is determined at a value that is an integral multiple of the arrangement period of the armature coils of the armature unit. Therefore, when the arrangement direction of the thrust generating magnets is parallel to that of the armature coils, the positional relationship between a thrust generating magnet and an armature coil opposing this magnet is similar to that of another thrust generating magnet and an armature coil opposing this magnet. Accordingly, when the magnetic pole unit and the armature unit are relatively moved to perform a translation in a desired direction, the direction of electric current supplied to the armature coil depends on the polarity of the magnetic pole surface opposing the armature unit. Basically, however, when an electric current is supplied to an armature coil opposing a thrust generating magnet to generate a thrust in the desired driving direction, the driving unit can similarly supply current other armature coils opposing the thrust generating magnets, which simplifies the control of motor driving.
Also, with the first planar motor device of the present invention, the side length of the magnetic pole surface of the thrust generating magnet is determined at a value longer than the arrangement period of the armature coils. It is also a value that is not equal to the integral multiple of the arrangement period of the armature coils. Accordingly, the positional relationship between the thrust generating magnet and the armature coil in which the thrust becomes zero in regardless of the current supplied to the armature coil does not exist. The thrust becomes zero, when the side length of the magnetic pole surface of the thrust generating magnet is an integral multiple of the arrangement period of the armature coils.
Therefore, according to the first planar motor device of the present invention, by utilizing the merits of the Lorentz force driving method that excels in controllability, thrust linearity, and positioning ability, a stable and high powered thrust can be generated by a simple control of the current supplied.
In the first planar motor device of the present invention, the magnetic pole unit can be structured further comprising an interpolating magnet arranged on a magnetic flux path formed on a magnetic pole surface side of the thrust generating magnet opposing the armature unit, the path formed between the thrust generating magnets which are adjacent in the row direction and the column direction, the interpolating magnet being a part of a magnetic circuit, and reinforcing a magnetomotive force. In such a case, on structuring a magnetic circuit, both the thrust generating magnets and the interpolating magnet serve as a magnetomotive source. This result in increasing in the absolute value of the magnetic flux density B of the magnetic flux formed on the current path of the armature coil due to the magnetic pole unit.
In general, in the case of increasing the numbers of the rows and columns of the arrangement of the thrust generating magnets, when the magnetic pole unit and the armature unit relatively moves and the position where the magnetic flux is created on the armature unit side also move, the polarity of the magnetic pole surfaces adjacent in the row direction and column direction alternately differ. This causes the direction of the magnetic flux to be frequently reversed. So, for example, in the case of using magnetic members to reduce the reluctance at the armature unit side, the direction of the magnetic flux is frequently reversed, in turn generating an eddy current in the magnetic member. As a result, the reluctance is increased, which prevents a high-density magnetic flux from being generated, increasing the energy loss.
Thus, according to the first planar motor device of the present invention, with consideration to this view, the thrust generating magnets can be arranged in a shape of a two-by-two matrix. In such a case, the frequency of the direction of the magnetic flux reversing at the armature unit side while the magnetic pole unit and the armature unit are relatively moving is minimized. Therefore, the magnetic circuit can keep a low reluctance, thus, making it possible for a high thrust to be generated and reducing the loss. Also, in such a case, with the magnet pole unit in which the thrust generating magnets are arranged in a square matrix shape so as to symmetrically generate a magnetic flux with a high magnetic flux density, the number of thrust generating magnets is minimized, naturally, simplifying the configuration.
With the first planar motor device of the present invention, the external shape of the magnetic pole surface of the armature unit opposing the magnetic pole unit or the magnetic pole surface of the thrust generating magnet may be of various shapes. However, the external shape of a surface of the armature coil which opposes the magnetic pole unit can be a square, and the magnetic pole surface of the thrust generating magnets can be of a square shape. In such a case, when the magnetic pole unit and the armature unit move relatively in one of two directions being perpendicular, electric current can be supplied to the armature coils arranged along in the moving direction similarly, as when these units move relatively in the other direction. That is, in the two directions perpendicular to each other, electric current can be symmetrically supplied to the armature coils. Accordingly, the magnetic pole unit and the armature unit can be relatively moved in the two-dimensional direction by a simplified control.
In the first planar motor device, various relations can be considered on the shape and arrangement of the armature coils, and the shape and arrangement of the thrust generating magnets. The current path length on an outer side of the armature coil can be respectively around 3 times longer than a current path on an inner side, a magnetic pole surface length of one side of the thrust generating magnets can be respectively 4 to 5 times longer than the current path on the inner side, and the arrangement period of the thrust generating magnets can be around 6 times longer than the current path on the inner side. In such a case, the arrangement period of the thrust generating magnets is twice, that is, the smallest integral multiple of the arrangement period when the armature coils are closely arranged in the shape of a matrix. Also, the length of one side of the thrust generating magnet may be determined so as to be a non-integral multiple of the length of, for instance, 4/3 to 5/3 times the length of the external of the armature coil.
And, with the first planar motor device of the present invention, the first planar motor device may further comprise a first magnetic member to support the armature coils at a side opposite to the magnetic pole unit. In such a case, the magnetic circuit is structured at the side opposite to the magnetic pole unit of the armature coils via the first magnetic member. Thus, a stable magnetic circuit with low reluctance can be structured, and the magnetic flux can be confined within the first magnetic member. Consequently, a magnetic flux having a high-density can be generated at the position where the armature coils are arranged, as well as prevent the members arranged at the side opposite to the magnetic pole unit of the armature coils from being magnetically affected.
According to the first planar motor device of the present invention, it can be structured to further comprise a second magnetic member to support the thrust generating magnets at a side opposite to the armature unit. In such a case, the magnetic circuit is structured at a side opposite to the armature unit via the second magnetic member. Thus, a stable magnetic circuit having a low reluctance can be configured, as well as confine a magnetic flux in the second magnetic member. Consequently, a magnetic flux having a high-density can be generated at positions where the armature coils are arranged. And the members arranged at the side opposite to the magnetic pole unit of the armature coils can be kept from being magnetically affected.
Also, with the first planar motor device in the present invention, it may further comprise at least one guide member arranged between the armature unit and the magnetic pole unit which is made of a material non-magnetic and non-conductive and forms the guide surface. A non-magnetic material, in this case, is a material which has permeability sufficiently small compared with that of magnetic materials, such as iron, and is almost equal to that of air. And, a non-conductive material, in this case, is a material, which has conductivity sufficiently low compared with that of conductive materials, such as copper, and is almost equal to that of air. In such a case, the magnetic pole unit levitated so that it is not in direct contact with the guide member by the exhausted air from the magnetic unit side to the guide member, and this state is maintained. Since the guide member is non-magnetic and non-conductive, it does not affect the magnetic flux generated by the magnetic pole unit. Accordingly, the magnetic pole unit and the guide member (thus, the armature unit) can easily be put into a noncontact state while the thrust of the planar motor device is maintained, thus, a high-speed relative movement by a low thrust can easily be achieved.
And, with the first planar motor device of the present invention further having the guide member, it may have a structure of further comprising a supporting member attached to the magnetic pole unit and has a first vent portion to exhaust a pressurized gas to the guide surface, the supporting member being adapted to support the magnetic pole unit by air levitation via a predetermined air gap. In such a case, the magnetic pole unit is supported by air levitation above the guide surface by the exhausting pressure of the pressurized air blown from the vent portion of the supporting member attached to the magnetic pole unit to the guide surface, that is, the static pressure of the pressurized air in the air gap between the supporting member and the guide surface. Then, by supplying electric current to a plurality of armature coils of the stator, the magnetic unit and the supporting member are integrally driven along the guide surface by the Lorentz force generated. It is preferable that the vent portion of the supporting member is arranged in the vicinity of the magnets of the magnetic pole unit, so as to support the magnetic pole unit more efficiently by air levitation.
The first planar motor device, which has the guide member and the supporting member, may further comprise a base which includes the guide member and forms a closed space in its interior where the plurality of armature coils are arranged. In such a case, since the armature coils which generates heat by the electric current supplied are housed in the closed space in the base, the thermal influence to the surrounding environment is reduced. In this case, the base is preferably made of a high heat insulating material.
In this case, the first planar motor device may have a structure of further comprising a cooling device which supplies a coolant to the closed space and cools the armature coils. In such a case, by supplying the coolant into the closed space by the cooling device the respective armature coils can be efficiently cooled. Thus, the armature coils are efficiently cooled, the thermal influence upon the surrounding environment is reduced, and the power consumption for cooling can be decreased.
With the first planar motor device, which has the guide member and the supporting member, it may have a structure further comprising a plurality of cases which respectively house the plurality of armature coils. In such a case, compared with when cases are not provided in the motor, the thermal influence on the surrounding environment by the heat generated by the coils can be reduced. In the case of this motor having such cases, the cases and the guide member are preferably made of a high heat insulating material.
It is preferable for the first planar motor device, to further comprise a cooling device to respectively cool an interior of the plurality of cases. In such a case, the armature coils which are respectively arranged in each case, can be individually and effectively cooled.
Also, the first planar motor device may be configured so that an upper surface of the cases respectively structure the guide surface. In such a case, since the cases serve as the guide member, there is no need to provide a guide member in addition to the cases, simplifying the configuration of the planar motor device.
Regardless of whether the first planar motor further having the guide member, includes the supporting member, this planar motor may further comprise a base which includes the guide member and forms a closed space in its interior where the plurality of armature coils are arranged. In such a case, as well, since the armature coils generating the heat by the current supplied are housed in the closed space of the base, the thermal influence on the surrounding environment by the heat generated by the coils can be reduced. In this case, as well, the first planar motor device may have a structure further comprising a cooling device which supplies a coolant to the closed space and cools the armature coils.
Also, with the first planar motor device further compring the guide member, regardless of whether it may have a supporting member, the first planar motor device may have a structure further comprising a plurality of cases which respectively house the plurality of armature coils. In this case, the thermal influence on the surrounding environment is reduced, in comparison with the case when cases are not provided in the motor. In the case of the planar motor device having such cases, this motor may preferably have a structure further comprising a cooling device to respectively cool an interior of the plurality of cases. Moreover, this motor may be configured so that an upper surface of the cases respectively structure the guide surface.
According to a second aspect of the present invention, there is provided a second planar motor device, comprising: an armature unit including a plurality of armature coils arranged in a matrix shape along a guide surface, which have a rectangular current path; and a magnetic pole unit arranged opposing the armature unit with respect to the guide surface including a plurality of thrust generating magnets which have a rectangular magnetic pole surface and are arranged so as to have a different polarity of an adjacent magnet pole surfaces alternately, and interpolating magnet to reinforce a magnetomotive force, which is arranged on a magnetic flux path formed on a magnetic pole surface side of the thrust generating magnet opposing the armature unit, the path formed between the thrust generating magnets which are adjacent, and the armature unit and the magnetic pole unit relatively move in a direction along the guide surface.
With the second planar motor device, since the magnetomotive force source becomes both the thrust generating magnets and the interpolating magnets on structuring the magnetic circuit, the absolute value of the magnetic flux density B of the magnetic flux generated on the current path of the armature coils due to the magnetic pole unit can be increased. Therefore, while reducing the power consumption of the armature unit, a high thrust can be stably generated by utilizing the merits of the Lorentz force driving method that excels in controllability, thrust linearity, and positioning ability.
Similarly as in the case of the first planar motor device of the present invention, with the second planar motor device of the present invention, it may have a structure in which an external shape of a surface of the armature coil which opposes the magnetic pole unit is a square, and the magnetic pole surface of the thrust generating magnets is of a square shape. Furthermore, a current path length on an outer side of the armature coil can be respectively around 3 times longer than a current path on an inner side, a magnetic pole surface length of one side of the thrust generating magnets can be respectively 4 to 5 times longer than the current path on the inner side, and the arrangement period of the thrust generating magnets can be around 6 times longer than the current path on the inner side.
And, similarly as in the case of the first planar motor device of the present invention, with the second planar motor device of the present invention, it may have a structure further comprising a first magnetic member to support the armature coils at a side opposite to the magnetic pole unit. Also, the second planar motor device of the present invention may further comprise a second magnetic member to support the thrust generating magnets at a side opposite to the armature unit. And, the second planar motor device may have a structure further comprising at least one guide member arranged between the armature unit and the magnetic pole unit which is made of a material non-magnetic and non-conductive and forms the guide surface.
Similarly as in the case of the first planar motor device of the present invention, with the second planar motor device of the present invention having the guide member, it may have a structure further comprising a supporting member attached to the magnetic pole unit and has a first vent portion for exhausting a pressurized gas to the guide surface, the supporting member being adapted to support the magnetic pole unit by air levitation via a predetermined air gap. Furthermore, the second planar motor device may have a structure, further comprising a base which includes the guide member and forms a closed space in its interior where the plurality of armature coils are arranged. And, the planar motor may further have a plurality of cases, which respectively house the plurality of armature coils individually.
In the case of the second planar motor device having the base, it may have a structure further comprising a cooling device which supplies a coolant to the closed space and cools the armature coils. And, with the second planar motor device, which further comprises a plurality of cases may further comprise a cooling device to respectively cool an interior of the plurality of cases. Further, this planar motor device may be configured so that an upper surface of the cases respectively structure the guide surface.
With the second planar motor device of the present invention which has the restricting elements or additional elements similar to the first planar motor device of the present invention, the restricting elements and additional elements in the second planar motor device act similarly, producing similar effects as of the first planar motor device.
According to a third aspect of the present invention, there is provided a third planar motor device, comprising: a magnetic pole unit which has at least one magnet and moves along a predetermined guide surface in two-dimensional directions; a supporting member attached to the magnetic pole unit and has a first vent portion to exhaust a pressurized gas to the guide surface, the supporting member being adapted to support the magnetic pole unit by air levitation via a predetermined air gap; and a stator including a plurality of armature coils arranged at a side opposite to the magnetic pole unit in respect to a guide surface in two-dimensional directions along the guide surface.
With the third planar motor device, the magnetic pole unit is supported by air levitation above the guide surface by the blowing pressure of the pressurized air blown from the vent portion of the supporting member attached to the magnetic pole unit to the guide surface, namely, the static pressure of the pressurized air in the air gap between the supporting member and the guide surface. Then, the magnetic unit and the supporting member are integrally driven along the guide surface by the Lorentz force which is generated by electric current being supplied to a plurality of armature coils of the stator.
That is, in this case, compared with the variable reluctance driving planar motor device which employs a magnetic attraction force as a driving force based on a driving principle, the magnetic attraction force acting between the magnet of the magnetic pole unit and the stator-side yoke is lower due to the fact that the armature coil is arranged between the magnet structuring the magnetic pole unit and the stator-side yoke. Therefore, the power consumption of the gas source which is required to supply the pressurized gas used to levitate the stator (that is, the magnetic pole unit and the supporting member), can be reduced. It is preferable that the vent portion of the supporting member is arranged in the vicinity of the magnets of the magnetic pole unit, to support the magnetic pole unit more efficiently by air levitation.
The third planar motor device of the present invention may be structured so that the magnetic pole unit is freely attachable to and detachable from the supporting member. In such a case the magnetic pole unit can be separated from the supporting member, therefore, the maintainability of the motor is enhanced.
The third planar motor device may be structured so that the supporting member has a second vent portion which exhausts a pressurized gas to the magnetic pole unit so as to support the magnetic pole unit by air levitation against a downward force when the magnetic pole unit is attached to the supporting member, the downward force acting in a direction of gravity and is a sum of a magnetic attraction force of the magnetic pole unit, the armature coil, and the stator and a weight of the magnetic pole unit itself. In such a case, when the magnetic pole unit is attached (or assembled) to the supporting member, the magnetic pole unit is supported by air levitation by the exhausting pressure of the pressurized gas released from the second vent portion of the supporting member. Thus, the magnetic pole unit can be prevented from being rapidly attracted to the supporting member by the magnetic attraction force acting between the magnetic pole unit and the stator. This simplifies the attachment of the magnetic pole unit to the supporting member. And, also in the case of detaching the magnetic pole unit from the supporting member, the exhausting pressure of the pressurized gas released from the second vent portion of the supporting member accelerates this separation operation. As a result, the attachment/detachment of the magnetic pole unit to the supporting member can be simplified, thus, the maintainability of the motor is enhanced even more.
In this case, needless to say, the first vent portion and the second vent portion may be connected separately to the supplying source of the pressurized air, and the pressurized gas may be released from the first vent portion individually from the second vent portion. However, with the third planar motor device of the present invention, the supporting member may further comprise a switching mechanism which switches an exhaustion of a gas between an exhaustion of a pressurized gas from the first vent portion and an exhaustion of a pressurized gas from the second vent portion. In such a case, the first vent portion and second vent portion of the pressurized gas can be connected to the same source, and the gas exhausting from the vent portion can be switched by the switching mechanism between the two vent portions. Therefore, the structure of the device can be simplified.
With the third planar motor device of the present invention, it is preferable that the supporting member further comprises a suction portion to vacuum chuck the supporting member to the guide surface, the supporting member being able to control a dimension of the predetermined air gap by adjusting an exhaustion pressure of the pressurized gas released from the first vent portion and a vacuum suction force of the suction portion. In such a case, even when there is an uneven portion on either the guide surface or the surface opposing the guide surface of the supporting member, by suppressing vibrations, the air gap between the guide surface and the surface opposing the guide surface of the supporting member (what is called a bearing gap) can be maintained at a desired dimension.
Furthermore, with the third planar motor device the supporting member can have an attachment/detachment mechanism to have the magnetic pole unit attached and detached. In such a case, the magnetic pole unit can be attached to and detached from the supporting member by the attaching/detaching mechanism, therefore, simplifies the attachment/detachment operation of the magnetic pole unit with the supporting member.
Also, the third planar motor device of the present invention may further have a structure comprising a base which forms the guide surface as well as form a closed space in its interior where the plurality of armature coils are arranged. In such a case, since the armature coils which generates heat by the electric current supplied are housed in the closed space in the base, the thermal influence to the surrounding environment is reduced. In this case, preferably, the base is made of a high heat insulating material.
The third planar motor device may have a structure further comprising a cooling device which supplies a coolant to the closed space and cools the armature coils. In such a case, the armature coils can respectively be cooled efficiently by the coolant supplied into the closed space by the cooling device. Thus, the armature coils are efficiently cooled, which reduces the thermal influence upon the surrounding environment, and the power consumption for cooling can also be reduced.
And, the third planar motor device may have a structure further comprising a plurality of cases which respectively house the plurality of armature coils. In such a case, the thermal influence on the surrounding environment due to the heat generation by the coils can be reduced compared with the case of not having the cases arranged in the device. When the device is provided with the cases, the cases and the guide member are preferably made of a high heat insulating material.
It is preferable for the third planar motor device to further comprise a cooling device to respectively cool an interior of the plurality of cases. In such a case, the armature coils, arranged in each case, can be individually and effectively cooled.
Also, the third planar motor device may be structured so that an upper surface of the cases respectively structure the guide surface. In such a case, the cases serve as the guide member, therefore making it possible to omit a separate guide member in addition to the cases, simplifying the structure.
According to a fourth aspect of the present invention, there is provided a fourth planar motor device, comprising: a magnetic pole unit which has at least one magnet and moves along a predetermined guide surface in two-dimensional directions; a base which forms the guide surface and has a closed space formed in its interior; an armature unit including a plurality of armature coils housed in the closed space of the base which are arranged in two-dimensional directions along the guide surface at predetermined intervals; and a cooling device which supplies a coolant into the closed space to respectively cool the armature coils.
With the fourth planar motor device, among the plurality of armature coils, electric current is supplied to the armature coil opposing the magnet of the magnetic pole unit. The magnetic pole unit is driven along the guide surface by the Lorentz force generated according to the amount and direction of the electric current supplied to the armature coil. In the case of continuously driving the magnetic pole unit in a certain direction, electric current is supplied to the armature coil opposing the magnet at each movement position of the magnetic pole unit. Therefore, the armature coil supplied with the electric current generates heat. However, the armature coils are housed in the closed space in the base, and the coolant is supplied to this closed space by the cooling device to cool the respective coils. Thus, the armature coil can be efficiently cooled, and the thermal influence to the surrounding environment is reduced. The power consumption for cooling, can also be reduced.
The fourth planar motor of the present invention may be configured so that the closed space is divided by a dividing member arranged on an opposite side to the guide surface of the plurality of armature coils into a first chamber where the plurality of armature coils are housed, and a second chamber formed by a remaining space, and an inlet opening and an outlet opening are respectively formed in the dividing member, and a coolant path is formed in the base in which a coolant supplied from the cooling device flows into the first chamber via the inlet opening and then flows out to the second chamber via the outlet opening. In such a case, the path of the coolant is formed in the base so that the coolant supplied from the cooling device flows into the first chamber via the inlet opening and then flows out into the second chamber via the outlet opening. Thus, not only can the first chamber in which the plurality of armature coils are housed be directly cooled by the coolant, but the dividing member can also be cooled in the second chamber. Consequently, the armature coils can be cooled more efficiently.
In this case, it is preferable for the fourth planar motor device to further comprise secondary cooling fins respectively made of a high thermal conductive material and arranged on the path of the coolant which flows out through the outlet opening. In such a case, the cooling efficiency of the path of the armature coil can be improved.
Also, the fourth planar motor device of the present invention may be configured so that the closed space formed within the base is divided into a plurality of small chambers which respectively house the armature coils, and the plurality of small chambers respectively have an inlet opening and an outlet opening to supply the coolant from the cooling device. In such a case, the armature coils are individually and respectively housed in the small chambers, and an outlet opening and an inlet opening for a coolant supplied from the cooling device are formed in each of the small chambers. Thus, the coolant supplied from the cooling device flows into the respective small chambers through the inlet opening and flows out through the outlet opening. Consequently, the small chambers, thus, the armature coils can be cooled individually and efficiently. In this case, the fourth planar motor device may have a structure of further comprising a plate-shaped non-magnetic member which serves as the guide surface and is arranged so as to cover the plurality of small chambers. In this case, a space may be arranged between the small chamber and the non-magnetic member.
Furthermore, needless to say, the small chambers may be formed, by dividing the closed space within the base by the dividing members. However, the fourth planar motor device may be configured so that the small chambers are respectively structured of a plate-shaped member arranged at a side opposite to the guide surface of the plurality of armature coils, and a plurality of box-shaped cases which respectively have an opening on a surface opposing the plate-shaped member and have an opposite side of the surface formed as the guide surface, and an inlet opening and an outlet opening to respectively supply a coolant to the small chambers are formed in the plate-like member in respect to the plurality of cases. In such a case, by arranging the plate-shaped member in the internal space of the base, and arranging the plurality of cases in which armature coils are already housed, at a predetermined position on the plate-shaped member, a plate (the guide surface) which appears to be a single plate, is formed on a surface opposite to the plate-shaped member. Accordingly, each of the small chambers, namely, the armature coils arranged in each case can be individually and efficiently cooled, as well as the base side (namely, the stator side) being easy to attach from a certain direction.
In this case, the fourth planar motor device may be structured so that terminals of the armature coils are exposed from an open end of the case, and a socket portion where the terminal is fitted is provided in a corresponding part of the plate-shaped member. In such a case, by simply attaching the respective cases to the plate-shaped member, the wiring for supplying electric current to each of the armature coil is also completed.
Also, the fourth planar motor device may be configured so that an additional chamber is arranged in an opposite side to the guide surface of the small chambers within the base, and a coolant path is formed in the base in which a coolant supplied from the cooling device flows into the case respectively via the inlet opening and then flows out to the additional chamber via the outlet opening. In such a case, the path of the coolant is formed in the base so that the coolant supplied from the cooling device flows into each case via the inlet opening and then flows out into the additional chamber via the outlet opening. Thus, not only can each case in which the plurality of armature coils are respectively housed be directly cooled by the coolant, but the plate-shaped member can also be cooled in the additional chamber side. Consequently, the armature coils can be cooled more efficiently.
And, it is preferable for the fourth planar motor device to further comprise secondary cooling fins respectively made of a high thermal conductive material and arranged on the path of the coolant which flows out through the outlet opening. In such a case, the cooling efficiency of the path of the armature coil can be improved.
Moreover, the fourth planar motor device of the present invention may be configured so that the armature coils are respectively a ring-shaped coil with a space formed in its central portion, and the cooling device supplies the coolant to each of the armature coils via the space formed in its central portion from an opposite side of the guide surface of the armature coils. In such a case, the side surface of the space formed in the central portion of the armature coil and the side surface facing the guide surface of the armature coils can be efficiently cooled, therefore, at least the thermal influence on the guide surface side can be reduced.
In this case, the fourth planar motor may further comprise straightening fins to regulate a path of the coolant which flows from the space formed in its central portion to its surroundings. In such a case, the straightening fins can regulate the path of the coolant flowing from the space in the central portion of the armature coils along the surface side of the guide-surface of the armature coil to the outlet opening formed at a predetermined position. Thus, by setting the path so that the coolant flowing along the surface side of the guide-surface of the armature coils uniformly as much as possible, the surface side of the guide-surface of the armature coils can be cooled evenly.
The fourth planar motor device of the present invention may be configured so that the base has a plurality of coolant injecting joints and at least one coolant discharging joint attached, and the cooling device has an end respectively connected the coolant injecting joint via a coolant supplying pipe, and also has another end connected to the coolant discharging joint via a coolant discharging pipe. In such a case, the coolant is supplied into the base through the cooling device, the coolant supplying pipe, and the plurality of coolant supplying joints. This coolant flows through the coolant passage in the base and cools each of the armature coils. Then, the coolant which temperature has risen as a result of this cooling operation, returns to the cooling device through the coolant discharging joint and the coolant discharging pipe, and cooled in the cooling device to be supplied again into the base to cool the armature coils. Thus the coolant is recycled through the cooling device and the base. That is, the armature coils can always be cooled by a predetermined amount of coolant, resulting to be an economical device.
According to a fifth aspect of the present invention, there is provided a fifth planar motor device comprising: a magnetic pole unit which has at least one magnet and moves along a predetermined guide surface in two-dimensional directions; a plurality of armature coils arranged with respect to the guide surface at predetermined intervals in two-dimensional directions along the guide surface at a side opposing the magnetic pole unit; and a plurality of cases which individually house the plurality of armature coils.
With the fifth planar motor device according to the present invention, among the plurality of armature coils, electric current is supplied to the armature coil opposing the magnet of the magnetic pole unit. The magnetic pole unit is driven along the guide surface by the Lorentz force generated according to the amount and direction of the electric current supplied to the armature coil. In the case of continuously driving the magnetic pole unit in a certain direction, electric current is supplied to the armature coil opposing the magnet at each movement position of the magnetic pole unit. Therefore, the armature coil supplied with the electric current generates heat. However, the armature coils are housed in the closed space in the base, and the coolant is supplied to this closed space by the cooling device to cool the respective coils. Thus, the armature coil can be efficiently cooled, and the thermal influence to the surrounding environment is reduced. In this case, preferably, the cases and the guide surface are made of high heat insulating materials.
The fifth planar motor device of the present invention may have a structure further comprising a cooling device to respectively cool an interior of the plurality of cases. In such a case, the armature coils provided in each cases can be individually and efficiently cooled.
Also, the fifth planar motor device of the present invention may be structured so that an upper surface of the cases respectively structure the guide surface. In such a case, the cases serve as the guide member. Thus, it is unnecessary to provide a guide member separately, in addition to the cases, simplifying the structure of the device.
According to a sixth aspect of the present invention, there is provided a stage device, comprising: a planar motor device according to the present invention; a movable body which moves integrally with one of a magnetic pole unit and an armature unit; and a controller which controls at least one of an amount and direction of electric current supplied respectively to the armature coils of the armature unit.
With this aspect, the controller controls at least one of the amount and direction of the electric current supplied to the armature coils of the planar motor device so as to relatively move the magnetic pole unit and the armature units in a desired direction of translation or rotation. Accordingly, the stage device excels in controllability, thrust linearity, and positioning ability, as well as being able to move the movable body with good accuracy.
The stage device of the present invention may have a structure further comprising: a position detecting system which detects a positional relationship between the magnetic pole unit and the armature unit; and the controller can control at least one of the amount and direction of electric current supplied respectively to the armature coils of the armature unit according to a detecting result of the position detecting system. In such a case, based on the accurate positional relationship between the magnetic pole unit and the armature unit the controller which is detected by the position detecting system, the controller controls at least one of the amount and direction of electric current supplied to the respective armature coils of the planar motor device. Consequently, the position of the movable body can be controlled with extremely high precision.
In this case, the stage may be configured so that the controller specifies respectively an intersection area between a magnetic flux path due to the magnetic unit and the armature coils based on the detection result of the position detecting system, and controls at least one of the amount and direction of electric current supplied respectively to the armature coils according the specified intersection area. In such a case, the controller first specifies an intersection area between the magnetic flux path due to the magnetic pole unit and the current path of electric current for the armature coil from the detection results of the position detecting system. Subsequently, in accordance with the specified intersection area, the controller then determines at least one of the amount and direction of the electric current to be supplied to each of the armature coil so as to provide the desired driving force in the desired direction. Then, based on the results, the controller controls at least one of the amount and direction of the electric current supplied to each of the armature coils, resulting in moving the movable body with high accuracy.
When the magnetic flux density distribution due to the magnets of the magnetic pole unit (namely, the thrust generating magnets) is almost uniform at the position where the corresponding armature coils are arranged, and the current density of the electric current flowing through each armature coils is almost uniform, the controller can obtain at least one of the amount and direction of the electric current supplied to the respective armature coils according to the volume of the specified intersection area. Moreover, if the shape of the current path of electric current supplied to the armature coils is approximately uniform with respect to the direction of the magnetic flux, the controller can obtain at least one of the amount and direction of the electric current supplied to each armature coils according to the area of the intersection area between the magnetic flux due to the magnetic pole unit and the surface, which faces the magnetic pole unit, of the armature coils.
According to a seventh aspect of the present invention, there is provided an exposure apparatus, comprising: an illumination system which emits an energy beam for exposure; and a stage device according to the present invention, which mounts an object to be arranged on a path of the energy beams. Thus, an object arranged on the path of the energy beam is mounted on the stage device of the present invention. Accordingly, the position of this object is controlled with good precision, resulting in an exposure with high precision.
The exposure apparatus of the present invention may be structured so that the object is a substrate onto which a predetermined pattern is transferred by exposing the energy beams. In such a case, positional control of the substrate to be exposed is performed with high accuracy by using the stage device of the present invention. Consequently, the predetermined pattern can be transferred onto the substrate with high precision.
According to an eighth aspect of the present invention, there is provided a making method of an exposure apparatus comprising: providing a planar motor device according to the present invention; providing a movable body which moves integrally with one of a magnetic pole unit and an armature unit; and providing a control unit which controls at least one of the amount and direction of electric current supplied respectively to the armature coils of the armature unit. According to this aspect, the exposure apparatus of the present invention can be made by mechanically, optically, and electrically combining the illumination system, the planar motor device, the movable body, the controller, and various other components with one another and adjusting these constituent elements.
The making method of the exposure apparatus of the present invention may further comprise providing a position detecting system which detects a positional relationship between the magnetic pole unit and the armature unit. In such a case, an exposure apparatus can be made which can control the position of the movable body in accordance with the accurate positional relationship of the magnetic pole unit and the armature unit detected by the detecting system.
Additionally, in a lithographic process, by using the exposure apparatus to transfer a predetermined pattern onto a substrate, a device having a fine pattern can be manufactured. Thus, according to another aspect of the present invention, there is provided a device manufactured by the exposure apparatus of the present invention. And in a lithographic process, the present invention is a device manufacturing method, in which a predetermined pattern is transferred onto the substrate by using the exposure apparatus that is made by the exposure apparatus making method of the present invention.